Sex hormones Flashcards
What is the definition of puberty?
Maturation of Reproductive Organs
Production of Sex-Steroids E.g. Oestradiol / Testosterone
Develop Secondary Sexual Characteristics
Attain capability to Reproduce
What are the 5 stages of breast development?
1-Elevation of papilla only
2-Breast bud with elevation of breast and papilla and enlargement of areola
3-Further enlargement of breast and papilla with no separation of their contours
4-Projection of areola and papilla to
form a secondary mound
5-Mature breast, projection of papilla only as areola conforms to breast contour
PBFAM
What are the 5 stages of male genitalia development?
1-Testes, penis, and scrotum
same size as early childhood
2-Early enlargement of testes 2-6 cm3; scrotal skin reddens
and changes in texture
3-Penis lengthens;
testes enlarge 6-12 cm3;
growth of scrotum
4-Further penile and scrotal growth;
testes 12-15 cm3
5-Genitalia adult in size and shape,
Testes >15 cm3
What are the 5 stages of pubic hair growth?
1-Vellus hair no different from abdominal hair
2-Slightly pigmented,
downy hair
3-Darker, coarser,
more curled hair
4-Adult pubic hair that does not reach thighs (axillary hair)
5-Adult hair now on thighs
ADCAT
What is adrenarche and when does it start?
Adrenal androgen production
-Starts ~2 years before gonadarche
What are the effects of oestradiol?
Breast Development
Hair Growth -
Pubic, Axillary
Sweat Gland Composition -
Skin oiliness / Acne
Changes to external genitalia
What are the effects of testosterone?
Deepening of Voice
Hair Growth -
Pubic then Axillary, facial
Sweat Gland Composition -
Skin oiliness / Acne
Changes to external genitalia
Between what ages do girls and boys go through puberty?
Boys:9-14
Girls:8-13
What the the pre and post pubertal testicular volumes?
Pre-4mls
Post-15mls
What is the first and late sign of female puberty?
First: Thelarche
Late: Menarche
What is gonadarche?
Activation of the HPG(Hypothalamic pituitary gonadal) axis
What is GnRH release like?
Pulsatile
What is the early and late onset of puberty coined as?
Early: Precocious
Late: Delayed
What changes occur during minipuberty, what is its purpose and when does it occur?
Occurs in infancy, includes
Testicular descent
Penile length
Sertoli cell maturation
Behavioral effects
-Is early activation of the HPG axis
What occurs to GnRH secretion during puberty?
Increased nocturnal GnRH pulsatility
When does menarche occur in regards to thelarche?
~2.3yrs after Thelarche.
Soon after Peak Height Velocity (PHV)
Mean Age 12.7 years (Range 10.7-16.1 years)
What is secondary amenorrhoea?
Common for Periods to be irregular / anovulatory for first 18months.
Periods start but then stop for at least 3-6 months
What is primary amenorrhoea?
Menarche later than16yrs
What occurs during the follicular+ovulatory phase of the menstrual cycle?
FSH rises, 2-3 follicles start to grow
-These produce E2 and Inhibin B
These reduce FSH by -ve feedback
This restricts the FSH window and non-dominant follicles undergo atresia
Dominant follicles-Are less dependent on FSH
A dominant ‘graafian’ follicle emerges, E2 levels soar, causing it to switch to +ve feedback
High E2 causes LH surge
LH spike causes ovulation
What occurs to the corpus luteum after ovulation and how can this be used as evidence of ovulation?
The corpus luteum begins to produce progesterone and E2
-Mid-luteal progesterone is evidence of corpus luteum perforation, therefore release of an oocyte
What is GnRH release like during the follicular phase and luteal phase
Follicular: Every 90-120mins
Luteal: Every 180-240mins
What is the mechanism for primary hypogonadism, what can cause it and what hormone levels does it produce?
Decreased testicular/ovarian testosterone/oestrogen release, so stronger negative feedback loop for hypothalamic GnRH release, so pituitary LH/FSH release is higher
Men - Eg Infection/
Trauma / Cancer of Testes
Woman - Menopause
High LH / FSH
Low E2 / Testo
What is the mechanism for secondary hypogonadism, what can cause it and what hormone levels does it produce?
No GnRH release, so no pituitary gonadotrophin release(FSH/LH), so reduced testosteron/oestrogen release.
Pituitary Tumour,
High Prolactin
Low (or normal) LH / FSH
Low E2 / Testo
What is AMH used to measure and where is it produced?
Anti-Müllerian Hormone (AMH) changes over the lifecourse and is very low at menopause
-Produced in granulosa cells in ovary
When does menopause occur and what is it called when it happens early?
Range: 45-55yrs
Median: 51 yrs
Premature:
1% occurs below 40yrs
Is there an andropause and what occurs?
‘Late onset hypogonadism’
The same amount of testosterone is produced but SHBG levels are increased, so total free/bioavailable testosterone is decreased
What are the components of total testosterone in the blood?
Free(Active testosterone)-2%
Albumin-bound(Bioavailable)-38%
SHBG-bound(Unavailable)-60%
During the day when is testosterone highest and what can cause a sudden dip in levels?
Morning-So needs to be measured before 11am
Glucose can cause a ~20% drop, so needs to be measured fasting
